Processing of municipal and other wastes

Abstract

The process provides for disposal of waste materials, including municipal waste such as garbage, industrial wastes, waste materials including rubber and plastics based materials, and ash waste from municipal waste incinerators and toxic waste incinerators. The waste is charged to a reactor, of a top-submerged lancing injector reactor system, containing a molten slag bath maintained in a turbulent condition, during charging of the waste, by top-submerged injection therein of a free-oxygen containing gas, using at least one top-submerged lance of the system. The waste is taken into the molten bath and is caused to circulate therein to a combustion/oxidation zone generated by the top-submerged injection. Constituents of the waste are subjected to free-oxygen of the injected gas in that zone and to heat energy of the slag, and thereby combusted/oxidised and/or decomposed.

We claim: 
     
       1. A process for disposal of waste materials, comprising charging waste to a reactor of a top-submerged lancing injector reactor system, said reactor containing a molten bath consisting essentially of slag; and maintaining the molten bath in a turbulent condition during charging of the waste by top-submerged injection therein of a free-oxygen containing gas, using at least one top-submerged lance of the system, such that the waste is taken into the molten bath and is caused to circulate therein to a combustion/oxidation zone generated in the molten bath by the top-submerged injection, wherein constituents of the waste are subjected to the free-oxygen of the injected gas and to heat energy of the slag and are thereby destroyed substantially by at least one of combustion and oxidation. 
     
     
       2. The process of claim 1, wherein the waste is in finely divided particulate form and is injected into the molten bath at or adjacent to the combustion/oxidation zone. 
     
     
       3. The process of claim 1, wherein the waste is in lump form and is charged to the molten bath through a feed port of the reactor. 
     
     
       4. The process of claim 1, wherein the waste is forced directly into the molten bath through a siphon built into a side wall of the reactor. 
     
     
       5. The process of claim 1, wherein the molten bath is maintained at a temperature of from 1100° C. to 1800° C. while the waste is being charged to the reactor. 
     
     
       6. The process of claim 5, wherein the molten bath is maintained at a temperature of from 1100° C. to 1400° C. 
     
     
       7. The process of claim 6, wherein the free-oxygen containing gas is injected into the bath at a rate providing at least a stoichiometric free-oxygen equivalent to the fuel-value of the waste, and the temperature of the molten bath is maintained by extracting or absorbing heat energy from the molten bath. 
     
     
       8. The process of claim 5, wherein the waste has a fuel-value sufficient to enable maintenance of the temperature of the molten bath. 
     
     
       9. The process of claim 5, wherein the waste has a fuel-value which is insufficient for maintenance of the temperature of the molten bath, and wherein said process further comprises supplying a sufficient quantity of fuel to the slag of the molten bath during said top-submerged injection to maintain the temperature. 
     
     
       10. The process of claim 9, wherein the fuel is selected from natural gas, fuel oil, coal and combinations thereof. 
     
     
       11. The process of claim 9, wherein the free-oxygen containing gas is injected into the bath at a rate providing at least a stoichiometric free-oxygen equivalent to the fuel-value of the waste, after allowance for oxygen required for combustion of said fuel supplied to the reactor, and the temperature of the molten bath is maintained by extracting or absorbing heat energy from the molten bath. 
     
     
       12. The process of claim 5, wherein the temperature is maintained by charging waste at a controlled rate, and by injecting free-oxygen containing gas at a controlled rate and with a controlled content of free-oxygen. 
     
     
       13. The process of claim 1, further comprising supplying free-oxygen containing gas to a reactor space above the molten bath during said top-submerged injection of free-oxygen into said bath to achieve post-combustion or after-burning of gases evolved from the molten bath and maintenance of evolved oxide species in an oxidized state. 
     
     
       14. The process of claim 13, wherein the free-oxygen containing gas supplied to the reactor space above the molten bath is selected from air, oxygen-enriched air and oxygen. 
     
     
       15. The process of claim 13, wherein the free-oxygen containing gas supplied to the reactor space above the molten bath provides oxygen in excess of stoichiometric requirements for substantially complete post-combustion/after-burning. 
     
     
       16. The process of claim 13, wherein the free-oxygen containing gas supplied to the reactor space above the bath is provided through a shroud pipe of the at least one lance of the reactor system. 
     
     
       17. The process of claim 1, wherein the free-oxygen containing gas injected into the molten bath is selected from air, oxygen-enriched air and oxygen. 
     
     
       18. The process of claim 1, further comprising constraining hot gases resulting from combustion/oxidation of the waste and from any post-combustion/after-burning in a reactor space above the molten bath, whereby said hot gases discharge via an off-take flue of the reactor, and subjecting discharged hot gases to rapid cooling. 
     
     
       19. The process of claim 18, wherein the cooling reduces the hot gases to a temperature below about 300° C. 
     
     
       20. The process of claim 18, wherein said rapid cooling is achieved by evaporative cooling by passing said discharged hot gases through a water spray or mist. 
     
     
       21. The process of claim 18, wherein said rapid cooling is achieved by quench cooling the discharged hot gases in a fluid bed boiler system. 
     
     
       22. The process of claim 1, wherein the waste includes metal species selected from elemental metal and oxidic material, and wherein said process further comprises discharging volatilisable metal species from the reactor as fume and taking non-volatilised metal species into solution in the slag of the molten bath. 
     
     
       23. The process of claim 1, wherein the waste includes toxic organic compounds, and wherein said process further comprises substantially fully destroying said toxic organic compounds by thermal cracking to provide an off-take gas substantially free of toxic compounds. 
     
     
       24. The process of claim 23, wherein said toxic organic compounds are selected from the group consisting of furans, dioxins and PCBs. 
     
     
       25. The process of claim 1, wherein the waste material is selected from the group consisting of municipal waste, industrial waste, rubber based waste, plastic based waste, and ash waste.